Theorem CNF_Manager::replaceITErec(const Expr& e, Var v, bool translateOnly)
{
// Quick exit for atomic expressions
if (e.isAtomic()) return d_commonRules->reflexivityRule(e);
// Check cache
Theorem thm;
bool foundInCache = false;
ExprHashMap<Theorem>::iterator iMap = d_iteMap.find(e);
if (iMap != d_iteMap.end()) {
thm = (*iMap).second;
foundInCache = true;
}
if (e.getKind() == ITE) {
// Replace non-Bool ITE expressions
DebugAssert(!e.getType().isBool(), "Expected non-Bool ITE");
// generate e = x for new x
if (!foundInCache) thm = d_commonRules->varIntroSkolem(e);
Theorem thm2 = d_commonRules->symmetryRule(thm);
thm2 = d_commonRules->iffMP(thm2, d_rules->ifLiftRule(thm2.getExpr(), 1));
d_translateQueueVars.push_back(v);
d_translateQueueThms.push_back(thm2);
d_translateQueueFlags.push_back(translateOnly);
}
else {
// Recursively traverse, replacing ITE's
vector<Theorem> thms;
vector<unsigned> changed;
unsigned index = 0;
Expr::iterator i, iend;
if (foundInCache) {
for(i = e.begin(), iend = e.end(); i!=iend; ++i, ++index) {
replaceITErec(*i, v, translateOnly);
}
}
else {
for(i = e.begin(), iend = e.end(); i!=iend; ++i, ++index) {
thm = replaceITErec(*i, v, translateOnly);
if (!thm.isRefl()) {
thms.push_back(thm);
changed.push_back(index);
}
}
if(changed.size() > 0) {
thm = d_commonRules->substitutivityRule(e, changed, thms);
}
else thm = d_commonRules->reflexivityRule(e);
}
}
// Update cache and return
if (!foundInCache) d_iteMap[e] = thm;
return thm;
}
